The central objective of the Resource Core (RC) is to assure that all investigators have access to the most appropriate expertise on a variety of cross-cutting issues. This Core is not designed to conduct independent research on its own, but to assist the research endeavors of each RTPRC project area. The members of this core will provide access to theoretical and technical support for theory development, program design, selection of measures, and data analyses. Therefore, members of the RC will conduct, and arrange for, training of investigators and practitioners (e.g., at RTPRC retreats, research meetings and workshops) and routinely review and comment on theoretical and methodological aspects of projects. They will also be available for consultation at the request of investigators. The specific aims of the RC are: 1.) Participate with the Administrative Core (AC) in the routine review of project area activities. The RC will identify areas of theoretical and substantive knowledge and expertise that are deemed essential to project areas and their individual projects, but underdeveloped among current RTPRC investigators, 2.) Identify experts in each of a variety of cross-cutting areas (including gender, racial/ethnic/cultural, and theoretical and methodological issues) who are willing to provide education and training to RTPRC investigators, and arrange for such training and consultation, 3.) Provide on-going methodological and statistical assistance to project areas regarding new and innovative analytic and statistical strategies, 4.) Train young investigators (including pre- and post-doctoral students) and long-time professionals in the use of contemporary methods for designing studies and analyzing etiology and prevention program drug use and mediator data, and 5.) Provide on-going assistance to RTPRC participants to assure that a) broad based dissemination efforts, including website maintenance, listserve directory updates and scheduled teleconferencing are routinely accomplished, b) projects have access to computers, software programs, instruments, and tools needed to accomplish project goals, and c) projects maintain up-to-date protection against viruses, worms and other potentially destructive computer invasions.